Controllable pitch propellers

ABSTRACT

IN A CONTROLLABLE PITCH PROPELLER, A DOUBLE CRANK BLADE TURNING MECHANISM HAVING A PIVOTABLE PISTON ASSEMBLY WITH SELF-ALIGNING CONNECTIONS TO ONE SET OF CRANKPINS, TO PROVIDE EQUAL LOADING ON ALL THE CRANKPINS.

July 11, 1972 A. FEROY 3,676,016

CONTROLLABLE PITCH PROPELLERS Filed Sept. 21, 1970 2 Sheets-Sheet 1 INVENTOR. AENE PERU) July 11, 1972 A. FEROY CONTROLLABLE PITCH PROPELLERS Filed Sept. 21, 1970 was BY 2 Sheets-Sheet 2 IN VENTOR.

United States Patent Ofi ce 3,676,016 CONTROLLABLE PITCH PROPELLERS Arne Ferny, 1921 S. 291st St., Federal Way, Wash. 98002 Filed Sept. 21, 1970, Ser. No. 73,915 Int. Cl. B63h 3/08 U.s. Cl. 416-157 9 Claims ABSTRACT OF THE DISCLOSURE In a controllable pitch propeller, a double crank bladeturning mechanism having a pivotable piston assembly with self-aligning connections to one set of crankpins, to provide equal loading on all the crankpins.

crank loading because the manufacturing accuracy necessary to make the various linkages equal in length (an absolute requirement in obtaining equal crank loading in such mechanisms) is impossible to obtain. Manufacturing inaccuracies in such mechanisms result in placing most or all of the load onto one crankpin causing the mechanisms to bind and become unworkable.

A mechanical blade-turning double crank mechanism having self-aligning connections between an axially movable control member and one set of crankpins is known to provide equal loading on the crankpins. Such mechanism, however, is located external of the hydraulic cylinder which operates it and contains many parts.

The principal object of this invention is to provide in a controllable pitch propeller, a simplified double crank blade-turning mechanism having a pivotable piston with self-aligning connections to one set of crankpins to provide equal loading on all the crankpins.

Another object of the invention is to provide in a controllable pitch propeller with four or more blades, a double crank blade-turning mechanism having a piston and a plate each independently pivotable in a hydraulic cylinder, with self-aligning connections between one set of crankpins and the piston and plate assembly to provide equal loading on all the crankpins. Another object of the invention is to provide. a blade-turning mechanism for controllable pitch propellers with a plurality of blades having only one cylinder and piston combined with self-aligning connections between the piston and one set of crankpins, the self-aligning connections being slidable in the cylinder wall to provide equal loading on the several crankpins. Another object is to provide a self-aligning linkage connection which will not cause locking or binding between any of the parts of a double crank mechanism.

Other objects are to provide a mechanism which is applicable to a controllable pitch propeller having any number of blades and to provide a blade turning mechanism having few parts, of practical and durable construction, and simple and inexpensive to manufacture. These and other objects of the invention will be apparent from the 3,676,016 Patented July 11, 1972 following description in connection with the drawings in which;

FIG. 1 is a longitudinal section of a three-bladed propeller hub;

FIGJZ is a plan view partially in section on line 2-2 of FIG. 1;

FIG. 3 is a transverse section on line 3-3 of FIG. 1;

FIG. 4 is a transverse section on line 4--4 of FIG. 1;

FIG. 5 is a longitudinal section of another embodiment of the invention showing a controllable pitch propeller hub having four blades;

FIG. 6 is a transverse section on line 6-6 of FIG. 5;

FIG. 7 is a transverse section on line 77 of FIG. 5;

FIG. 8 is a diagrammatic transverse section showing the pressure areas of a five-bladed controllable pitch propeller;

- FIG. 9 is an enlarged detail section of a self-aligning connection either in the pivotable piston or plate.

Referring to the drawings, propeller hub 10 is bolted to shaft 11 by cap screws 12. Propeller hub 10 is provided with sockets '13 each of which receives flange 14 attached to propeller blade 15. Flange 14 is provided with two crankpins 16. Crossheads 17 and 18 are slidable on the inner surface of flange 14 and have slots 19 and 20 respectively. Sliding block 21 is pivoted on one crankpin 16 of flange 14 and is slidable in slot 19 of crosshead 17. Sliding block 22 is pivoted on the other crankpin 16 of flange 14 and is slidable in slot 20 of crosshead 18. Crosshead 18 is bolted to cylinder 23 by cap screws 24. Bolt 26 is' slidable in wall of cylinder 23 and connects crosshead 1'7. to piston 25 with washer 36 and retainer screw 27. Bolt 26 and washer 36 are provided with spherical surfaces 28 and 29respectively which mate with and slide on spherical surfaces 30 and 31 of piston 25 and retainer screw 27 respectively, to form a flexible self-aligning connection'between piston 25 and crosshead 17 as shown in FIG; 9. Tubes 32 and 33 are flexibly connected to piston '25 and have fluid outlets to the forward and aft portions respectively of cylinder 23.

Forward portion 34 of cylinder 23 is provided with slots 35 which serve as sliding guides for and prevent lateral movement of the crossheads.

FIGS. 1-4 illustrates a three-bladed controllable pitch propeller with three crossheads 17 each being connected to piston 25 with flexible self-aligning connections. Three is the maximum number of connection points any such self-aligning member may have and provide equal loading on all crankpins.

FIGS. 5-7 illustrate another embodiment of the invention of a four bladed controllable pitch propeller. Crosshead 18 is connected to forward portion 34 of cylinder 23 with key 37. Bolt 26 is sldable in wall of cylinder 23 and connects two diametrically opposite crossheads 17 to piston 25 with washer 36 and retainer screw 27. Spherical surfaces 28 and'29 of bolt 26 and washer respectively mate withand slide on spherical surfaces 30 and 31 of piston 25 and retainer screw 27 respectively, to form a flexible self-aligning connection between piston 25 and crosshead 17. Bolts 38 are slidable in Wall of cylinder 23 and extend thru piston 25 connecting the remaining two crossheads 17 to plate 39. Plate 39 is position adjacent to and in sealing contact with piston 25. The connection between bolt 38 and plate 39 is also self-aligning, i.e., spherical surfaces 28 and 29 of bolt 38 and washer 36 mate with and slide on surfaces 30 and 31 of piston 25 and retainer screw 27.

Seal 41 is placed between piston 25 and plate 39 and separates area A from the remainder of the piston area.

The fluid chamber formed between piston 25 and plate 39 inside of seal 41 encloses bolts 38 and communicates with the forward end of cylinder 23 through hole 42 in piston 25. The piston area external of area A communicates with the aft end of cylinder 23. In a four bladed controllable pitch propeller both areas are of equal size.

Forward portion 34 of cylinder 23 is provided with two ports, one port in communication with each end of cylinder 23. Servo valve 40 is attached to the end of control rod 43 which also serves as fluid supply line causing oil under pressure to move the cylinder 23 and piston 25 in opposite directions to control the pitch of the propeller from forward position to neutral and reverse, and return.

FIG. 8 illustrates diagrammatically the pressure areas of a five-bladed controllable pitch propeller arrangement in which equal loading is obtained on all the crankpins. Bolt 26 is slidable in wall of cylinder 23 and connects three crossheads 17 to piston 25 with self-aligning connections. Bolts 38 are slidable in wall of cylinder 23, extend thru piston 25 and connect the remaining two crossheads 17 to plate 39 with self-aligning connection. Plate 39 is located adjacent to and in sealing contact with piston 25. Seal 44 is placed between piston 25 and plate 39 separating area B from the remainder of the piston area. The fluid chamber formed between piston 25 and plate 39 inside of seal 44 encloses bolts 38 and communicates with the forward end of cylinder 23. The piston area external of area B communicates with the aft end of cylinder 23. In a five-bladed controllable pitch propeller the area inside seal 44 is of the total piston area, the force resulting from pressure acting on this area being transmitted to plate 39 and the two crankpins to which plate 39 is connected. The force resulting from pressure acting on the area external of seal 44 is transmitted to piston and the three crankpins to which the piston is connected.

In operation, referring to FIGS. 1-4, fluid in lines 32 or 33 is directed to one side of piston 25 causing cylinder 23 to move in one direction and piston 25 to move in the opposite direction. Cylinder 23 (being connected by crossheads 18 and sliding blocks 22 to one set of crankpins 16) and piston 25 (being connected by crossheads 17 and sliding blocks21 to the other set of crankpins 16) coact to rotate flanges 14 and propeller blades 15 to control the pitch of the propeller from full-speed forward to fullspeed reverse and vice versa. Since spherical surfaces 28 and 29 are concentric with surfaces 30 and 31 respectively, the connections formed at these surfaces are therefore self-aligning and allow piston 25 to pivot and align itself to rest with equal force on bolts 26 thus loading the crankpins equally.

In operation of the embodiment of the invention shown in FIGS. 5-7, axial movement of control rod 43 will direct fluid to one end of cylinder 23 causing piston 25 to move in one direction and cylinder 23 to move in the opposite direction. When fluid is directed into the forward end of cylinder 23, for example, exerting a force on piston 25, bolts 26 and connected crankpins 16, such fluid also enters into the space between piston 25 and plate 39 inside of seal 41 thru hole 42 in piston 25 and exerts a force on plate 39, bolts 38 and the crankpins 16 to which bolts 38 are connected. Since the effective pressure areas of piston 25 and plate 39 are proportional to the number of connected crankpins, and since all the connections are selfaligning, the piston and plate may pivot independently and align themselves to rest with equal loading on all the crankpins. V

In operation of a controllable pitch propeller having five blades as shown in FIG. 8, when fluid is directed to the end of piston 25 exerting a force on the piston and the three connected crankpins, such fluid also enters into the space between piston 25 and plate 39 inside of seal 44 and exerts a force on plate 39 and its two connected crank- 4 pins. The net forces acting on the piston and plate are proportional to the piston areas outside and inside of seal 44 respectively, as well as to the number of connected crankpins, and is therefore distributed equally to all the crankpins thru the flexible self-aligning connections.

In the embodiments of the invention shown in FIGS. 5-8 piston 25 and plate 39 are placed adjacent to one another to accommodate the seal and to insure sealing between the two pressure areas, yet provided with sufficient separation to allow piston 25 and plate 39 to pivot independently and align themselves to rest on their respective crankpins.

Having described'the invention and its operation, it is obvious that the objects stated have been attained in a practical manner. While certain specific embodiments of the invention as applied to controllable pitch propellers have been shown and described, it is understood that the invention may be applied to double-crank mechanisms in general, and that changes may be made in the construction and arrangement of the various parts without departing from the spirit or scope of the invention as expressed in the following claims.

I claim:

1. In a controllable pitch propeller having a propeller hub and a plurality of blades radiating therefrom, a blade turning mechanism comprising a flange on each blade and operably seated in said hub, first and second crankpins on each flange, an axially movable hydraulic cylinder in said hub, operable connections between said cylinder and the first crankpins; an axially movable piston unit in said cylinder and operable connections between said piston unit and the second crankpins, said connections including flexible self-aligning joints on said piston unit within said cylinder to permit said piston unit to pivot and align itself within said cylinder to rest equally on said connections and to provide equal loading on all the crankpins; and means for moving said cylinder and piston unit in opposite direction to control the pitch of said blades from forward position to neutral and reverse, and return.

2. Structure as claimed in claim 1, said connections between said piston unit and the second crankpins slidable in a wall of said cylinder.

3. Structure as claimed in claim 1, said flexible selfaligning-joints comprising mating spherical surfaces to allow pivoting of said piston unit within said cylinder to provide equal loading on said crankpins.

4. Structure as claimed in claim 1, the said means for moving said cylinder and piston unit in opposite directions comprising means for supplying oil under pressure to said cylinder on either side of said piston unit.

. 5. Structure as claimed in claim 6, said piston and plate placed slightly apart to accommodate said seal and to permit said piston and plate to pivot independently within said cylinder and align themselves to rest on their respective connections to provide equal loading on the several crankpins.

6. Structure as claimed in claim 1, said piston unit comprising a piston and a plate adjacent to said piston, a seal between said piston and said plate; said operable connections between said piston unit and the second crankpins comprising operable connections between said piston and certain ones of the second crankpins and operable connections between said plate and the remainder of the second crankpins.

7. Structure as claimed in claim 5, said operable connections to said plate and to said remainder of the second crankpins slidably mounted through said piston, said seal surrounding and defining an area on said plate, a channel through said piston communicating with the region defined by said seal bet-ween said plate and said piston.

8. Structure as claimed in claim 7, wherein said area on said plate defined by said seal is proportional to the number of operable connections to said plate.

.9. Structure as claimed in claim 6, said flexible selfaligning joints comprising mating spherical surfaces to allovy pivoting of said piston and plate to provide equal FOREIGN PATENTS 1ad1ng on sald crankpms- 424,678 5/1967 Switzerland 416168 860,080 2/1961 Great Britain 416--157 References Clted 3,393,749 7/1968 Femy C. F. SCHIMIKOWSKI, Asslstant Exammer 2,686,569 8/1954 Bruce 416157 US. Cl. X.R. 3,051,248 8/1962 Hatcher 416-157 416167 

